Wireless sensor with oppositely positioned antenna and sensing circuitry

ABSTRACT

A wireless sensor includes a radio frequency (RF) front end, a sensing element, and a processing module. The RF front end receives a request for sensed data from a sensing computing device and sends a coded digital value to the sensing computing device via the RF signal. The sensing element senses an environmental condition of an item. The processing module determines an effect on an operational parameter of an RF front end of the wireless sensor as a result of the sensing element sensing the environmental condition and while receiving the RF signal. The processing module also adjusts tuning of the RF front end to mitigate the effect on the operational parameter and equates an amount of adjusting of the tuning of the RF front end to a coded digital value.

CROSS REFERENCE TO RELATED PATENTS

The present U.S. Utility Patent Application claims priority pursuant to35 U.S.C. § 120 as a continuation of U.S. Utility application Ser. No.15/430,899, entitled “WIRELESS SENSOR WITH OPPOSITELY POSITIONED ANTENNAAND SENSING CIRCUITRY”, filed Feb. 13, 2017, issuing as U.S. Pat. No.10,348,419 on Jul. 9, 2019, which claims priority pursuant to 35 U.S. C.§ 119(e) to U.S. Provisional Application No. 62/295,023, entitled “RFIDSENSORS WITH DISTALLY DISPOSED SENSING INTEGRATED CIRCUIT”, filed Feb.13, 2016, which is hereby incorporated herein by reference in itsentirety and made part of the present U.S. Utility Patent Applicationfor all purposes.

U.S. Utility patent application Ser. No. 15/430,899 further claimspriority pursuant to 35 U.S.C. § 120 as a continuation-in-part of U.S.Utility application Ser. No. 14/879,088, entitled “RADIO FREQUENCYIDENTIFICATION (RFID) MOISTURE TAG(S) AND SENSORS WITH EXTENDED SENSINGVIA CAPILLARIES”, filed Oct. 10, 2015, issued as U.S. Pat. No. 9,582,981on Feb. 28, 2017, which claims priority pursuant to 35 U.S.C. § 119(e)to U.S. Provisional Application No. 62/061,257, entitled “RADIOFREQUENCY IDENTIFICATION (RFID) MOISTURE TAGS AND SENSORS”, filed Oct.8, 2014, U.S. Provisional Application No. 62/079,369, entitled “RADIOFREQUENCY IDENTIFICATION (RFID) MOISTURE TAGS AND SENSORS”, filed Nov.13, 2014, U.S. Provisional Application No. 62/147,890, entitled “RADIOFREQUENCY IDENTIFICATION (RFID) MOISTURE TAGS AND SENSORS WITH EXTENDEDSENSING”, filed Apr. 15, 2015, and U.S. Provisional Application No.62/195,038, entitled “RFID MOISTURE TAGS AND SENSORS WITH EXTENDEDSENSING VIA CAPILLARIES”, filed Jul. 21, 2015.

STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT—NOTAPPLICABLE

INCORPORATION-BY-REFERENCE OF MATERIAL SUBMITTED ON A COMPACT DISC—NOTAPPLICABLE

BACKGROUND OF THE INVENTION Technical Field of the Invention

This invention relates generally to wireless communications and moreparticularly to wireless sensors and applications thereof.

Description of Related Art

Wireless communication systems are known to include wirelesstransceivers that communication directly and/or over a wirelesscommunication infrastructure. In direct wireless communications, a firstwireless transceiver includes baseband processing circuitry and atransmitter to convert data into a wireless signal (e.g., radiofrequency (RF), infrared (IR), ultrasound, near field communication(NFC), etc.). Via the transmitter, the first wireless transceivertransmits the wireless signal. When a second wireless transceiver is inrange (e.g., is close enough to the first wireless transceiver toreceive the wireless signal at a sufficient power level), it receivesthe wireless signal via a receiver and converts the signal intomeaningful information (e.g., voice, data, video, audio, text, etc.) viabaseband processing circuitry. The second wireless transceiver maywirelessly communicate back to the first wireless transceiver in asimilar manner.

Examples of direct wireless communication (or point-to-pointcommunication) include walkie-talkies, Bluetooth, ZigBee, RadioFrequency Identification (RFID), etc. As a more specific example, whenthe direct wireless communication is in accordance with RFID, the firstwireless transceiver may be an RFID reader and the second wirelesstransceiver may be an RFID tag.

For wireless communication via a wireless communication infrastructure,a first wireless communication device transmits a wireless signal to abase station or access point, which conveys the signal to a wide areanetwork (WAN) and/or to a local area network (LAN). The signal traversesthe WAN and/or LAN to a second base station or access point that isconnected to a second wireless communication device. The second basestation or access point sends the signal to the second wirelesscommunication device. Examples of wireless communication via aninfrastructure include cellular telephone, IEEE 802.11, public safetysystems, etc.

In many situations, direct wireless communication is used to gatherinformation that is then communicated to a computer. For example, anRFID reader gathers information from RFID tags via direct wirelesscommunication. At some later point in time (or substantiallyconcurrently), the RFID reader downloads the gathered information to acomputer via a direct wireless communication or via a wirelesscommunication infrastructure.

In many RFID systems, the RFID tag is a passive component. As such, theRFID tag has to generate one or more supply voltages from the RF signalstransmitted by the RFID reader. Accordingly, a passive RFID tag includesa power supply circuit that converts the RF signal (e.g., a continuouswave AC signal) into a DC power supply voltage. The power supply circuitincludes one or more diodes and one or more capacitors. The diode(s)function to rectify the AC signal and the capacitor(s) filter therectified signal to produce the DC power supply voltage, which powersthe circuitry of the RFID tag.

Once powered, the RFID tag receives a command from the RFID reader toperform a specific function. For example, if the RFID tag is attached toa particular item, the RFID tag stores a serial number, or some otheridentifier, for the item. In response to the command, the RFID tagretrieves the stored serial number and, using back-scattering, the RFIDtag transmits the retrieved serial number to the RFID reader.

For instance, in automobiles, wireless tire pressure monitoring sensorsare used to provide tire pressure information to an automobile'scomputer. The sensors may indirectly or directly sense tire pressure.For example, indirect sensing calculates tire pressure from measuredrevolutions of the tire via the sensor. As another example, directsensing measures the tire pressure from inside the tire. Direct sensingprovides a more accurate measure of tire pressure than indirect sensing,but does so at a cost. In particular, direct wireless sensors include abattery and micro-electromechanical semiconductor (MEMS) circuitry tosense the tire pressure.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING(S)

FIG. 1 is a schematic block diagram of an embodiment of a communicationsystem in accordance with the present invention;

FIG. 2 is a schematic block diagram of an embodiment of a computingdevice in accordance with the present invention;

FIG. 3 is a schematic block diagram of an example of a sensor computingdevice communicating with a wireless sensor in accordance with thepresent invention;

FIG. 4 is a schematic block diagram of an embodiment of a wirelesssensor in accordance with the present invention;

FIG. 5 is a logic diagram of an example of determining a digital valueby a wireless sensor in accordance with the present invention;

FIG. 6 is a schematic block diagram of an embodiment of an antenna andtuning circuit of a wireless sensor in accordance with the presentinvention;

FIG. 7 is a schematic block diagram of another embodiment of a wirelesssensor in accordance with the present invention; and

FIG. 8 is a schematic block diagram of another embodiment of a wirelesssensor in accordance with the present invention.

DETAILED DESCRIPTION OF THE INVENTION

FIG. 1 is a schematic block diagram of an embodiment of a communicationsystem 10 that includes a plurality of sensor computing device 12, aplurality of user computing devices 14, a plurality of wireless sensors16-1 through 16-4 (e.g., passive or active), one or more wide areanetworks (WAN), and one or more local area networks (LAN). The wirelesssensors 16-1 through 16-4, when activated, sense one or more of avariety of conditions. For example, one wireless sensor senses for thepresence, absence, and/or amount of moisture in a given location (e.g.,in a room, in a manufactured item or component thereof (e.g., avehicle), in a bed, in a diaper, etc.). As another example, a wirelesssensor senses pressure on and/or in a particular item (e.g., on a seat,on a bed, in a tire, etc.).

As yet another example, a wireless sensor senses temperature within aspace and/or of an item (e.g., surface temperature of the item, in aconfined space such as a room or a box, etc.). As a further example, awireless sensor senses humidity within a space (e.g., a room, a closet,a box, a container, etc.). As a still further example, a wireless sensorsenses the presence and/or percentages of a gas within a space (e.g.,carbon monoxide in a car, carbon monoxide in a room, gas within a foodcontainer, etc.). As an even further example, a wireless sensor sensesthe presence and/or percentages of light within a space. As yet afurther example, a wireless sensor senses the presence, percentages,and/or properties of one or more liquids in a solution. In one moreexample, a wireless sensor senses location proximity of one item toanother and/or the proximity of the wireless sensor to an item (e.g.,proximity to a metal object, etc.).

In general, the sensor computing devices 12 function to collect thesensed data from the wireless sensors and process the sensed data. Forexample, a wireless sensor generates a coded value representative of asensed condition (e.g., amount of moisture). A sensor computing device12 receives the coded value and processes it to determine an accuratemeasure of the sensed condition (e.g., a value corresponding to theamount of moisture such as 0% saturated, 50% saturated, 100% saturated,etc.).

The user computing devices 14 communicate with one or more of the sensorcomputing devices 12 to gather the accurate measures of sensedconditions for further processing. For example, assume that the wirelesscommunication system is used by a manufacturing company that hasmultiple locations for assembly of its products. In particular, LAN 1 isat a first location where a first set of components of products areprocessed and the LAN 2 is at a second location where second componentsof the products and final assembly of the products occur. Further assumethat the corporate headquarters of the company is at a third location,where it communicates with the first and second locations via the WANand LANs.

In this example, the sensor computing device 12 coupled to LAN 1collects and processes data regarding the first set of components assensed by wireless sensors 16-1 and 16-2. The sensor computing device 12is able to communicate this data to the user computing device 14 coupledto the LAN 1 and/or to the computing device 14 at corporate headquartersvia the WAN. Similarly, the sensor computing device 12 coupled to LAN 2collects and processes data regarding the second set of components andfinal assembly as sensed by wireless sensors 16-3 and 16-4. This sensorcomputing device 12 is able to communicate this data to the usercomputing device 14 coupled to the LAN 2 and/or to the computing device14 at corporate headquarters via the WAN. In such a system, real timemonitor is available locally (e.g., via the LAN) and is furtheravailable non-locally (e.g., via the WAN). Note that any of the usercomputing devices 14 may receive data from the any of the sensorcomputing devices 12 via a combination of LANs and the WAN.

FIG. 2 is a schematic block diagram of an embodiment of a computingdevice 12 and/or 14 that includes a computing core 20, one or more inputdevices 48 (e.g., keypad, keyboard, touchscreen, voice to text, etc.),one or more audio output devices 50 (e.g., speaker(s), headphone jack,etc.), one or more visual output devices 46 (e.g., video graphicsdisplay, touchscreen, etc.), one or more universal serial bus (USB)devices, one or more networking devices (e.g., a wireless local areanetwork (WLAN) device 54, a wired LAN device 56, a wireless wide areanetwork (WWAN) device 58 (e.g., a cellular telephone transceiver, awireless data network transceiver, etc.), and/or a wired WAN device 60),one or more memory devices (e.g., a flash memory device 62, one or morehard drives 64, one or more solid state (SS) memory devices 66, and/orcloud memory 96), one or more peripheral devices, and/or a transceiver70.

The computing core 20 includes a video graphics processing unit 28, oneor more processing modules 22, a memory controller 24, main memory 26(e.g., RAM), one or more input/output (I/O) device interface module 36,an input/output (I/O) interface 32, an input/output (I/O) controller 30,a peripheral interface 34, one or more USB interface modules 38, one ormore network interface modules 40, one or more memory interface modules42, and/or one or more peripheral device interface modules 44. Each ofthe interface modules 36-44 includes a combination of hardware (e.g.,connectors, wiring, etc.) and operational instructions stored on memory(e.g., driver software) that is executed by the processing module 22and/or a processing circuit within the respective interface module. Eachof the interface modules couples to one or more components of thecomputing device 12-14. For example, one of the 10 device interfacemodules 36 couples to an audio output device 50. As another example, oneof the memory interface modules 42 couples to flash memory 62 andanother one of the memory interface modules 42 couples to cloud memory68 (e.g., an on-line storage system and/or on-line backup system).

The transceiver 70 is coupled to the computing core 20 via a USBinterface module 38, a network interface module 40, a peripheral deviceinterface module 44, or a dedicated interface module (not shown).Regardless of how the transceiver 70 is coupled to the computing core,it functions to communication with the passive wireless sensors.

FIG. 3 is a schematic block diagram of an example of a sensor computingdevice 12 communicating with a wireless sensor 16 (e.g., any one of 16-1through 16-4). The sensor computing device 12 is illustrated in asimplified manner; as such, it shown to include the transceiver 70, anantenna 96, the processing module 22, and the memory (e.g., one or more26 and 62-68). The wireless sensor 16 includes an RF front end 75 (e.g.,receiver section, transmitter section, antenna, and/or a tuningcircuit), a processing module 84, and memory 88.

In an example, the sensing element 58 of the wireless sensor 16 sensesan environmental condition 65 of an object or item. The environmentcondition 65 includes, but is not limited to, one or more of moisture,temperature, pressure, humidity, altitude, sonic wave (e.g., sound),human contact, surface conditions, tracking, location, etc. The objector item includes one or more of, but is not limited to, a box, apersonal item (e.g., clothes, diapers, etc.), a pet, an automobilecomponent, an article of manufacture, an item in transit, blood, liquid,gas, etc. The sensing element 58 senses the environmental condition(e.g., moisture) and, as a result of the sensed condition, the sensingelement 58 affects 63 an operational parameter (e.g., input impedance,quality factor, frequency, etc.) of an RF front end 75.

As a specific example, the sensing element 58, as a result of the sensedenvironmental condition 65, affects the input impedance of the antennastructure and/or of the tuning circuit (e.g., a tank circuit thatincludes one or more capacitors and one or inductors having a resonantfrequency corresponding to the carrier frequency of the RF signal) ofthe RF front end 75. In response to the impedance change, the processingmodule 84 adjusts the resonant frequency of the tuning circuit tocompensate for the change in input impedance caused by the sensedenvironmental condition. The amount of adjustment is reflective of thelevel of the environmental condition (e.g., a little change correspondsto a little moisture; a large change corresponds to a large amount ofmoisture). The processing module 84 generates a coded digital value torepresent the amount of adjustment and conveys the coded value to thesensor computing device 12 via the transmitter section and the antennaof the RF front end 75 using back-scattering.

In addition to processing the sensed environmental condition, theprocessing module 84 processes a power level adjustment. For example, apower detection circuit of the wireless sensor 16 detects a power levelof a received RF signal. In one embodiment, the processing moduleinterprets the power level and communicates with the sensor computingdevice 12 to adjust the power level of the RF signal transmitted by thecomputing device 12 to a desired level (e.g., optimal for accuracy indetecting the environmental condition). In another embodiment, theprocessing module 84 includes the received power level data with theenvironmental sensed data it sends to the sensor computing device 12 sothat the computing device can factor the power level into thedetermination of the environmental condition.

FIG. 4 is a schematic block diagram of an embodiment of a wirelesssensor that includes a substrate 100, an antenna 80 (e.g. dipole,monopole, spiral, meandering trace, etc.), a transmission line 102, thesensing element 58, and a sensor integrated circuit (IC) 17. The sensorIC 17 includes the processing module 84, the memory 88, a transmittersection 94, a receiver section 92, a power harvesting circuit 82, apower detection circuit 86, and a tuning circuit 90. The processingmodule 84 is configured to include a controller 37 and a detectioncircuit 35.

In an example of operation, the wireless sensor is associated with anitem and an identifier of the item is stored in the memory 88. The itemis one or more of a gas, liquid, solid, composition, article ormanufacture, a bodily fluid (e.g., urine, blood, saliva, etc.), ananimal, and an inanimate object (e.g., a wall, a chair, an automobilepart, etc.). The wireless sensor may be directing attached to the itemor it may sense the item through the item's container (e.g., sensingtemperature and/or level of blood in a bag).

In a specific example, the item and/or the container have propertiesthat interfere with RF communications. In particular, the item and/orcontainer is electrically conductive, which substantially attenuates RFsignals in its immediately surrounding area. As such, if the antenna 80were place over the item and/or the container, the ability for thesensor computing device and the wireless sensor to communicate via RFsignals would be severely compromised and, in many instances, prevented.

To substantially overcome this issue, the antenna 80 is placed at oneend of the substrate 100 (e.g., a flexible printed circuit board and/ora printed plastic membrane) and the sensing element 58 is placed at theother end. When the wireless sensor is place on the item or container,the end with the sensing element 58 is placed proximal to the item tosense conditions of the item and the antenna end of the wireless sensoris positioned away from the item and/or container to substantially avoidRF signal interference of the item and/or container.

The sensing element 58 may be one of a variety of sensors sensing one ormore of a variety of conditions. For example, the sensing elementmeasures the temperatures of fluids, such as blood bags. As anotherexample, the sensing element senses moisture or temperature inside of acontainer that functions like an RF shield (e.g., metal, cavities inautomobile body parts, etc.). As yet another example, the sensingelement senses moisture or temperature at a location with overlayingmetal or electronics that block the RF signal (e.g., the floor of a car,a metallic panel, a speaker, an audio amplifier, other electronics, acrib, a mattress pad, etc.). As a further example, the sensing elementsenses moisture or temperature at location that is physically too smallto fit an antenna but can accommodate the tip of the tail.

For the sensing computing device 12 to communicate with the wirelesssensor 16, the sensor 16 first generates a power supply voltage (ormultiple power supply voltages) from an RF (radio frequency) signaltransmitted by the sensing computing device 12. For example, the RFsignal 61 is a continuous wave signal and uses amplitude shift keying(ASK) or other amplitude-based modulation scheme to convey data.

The power harvesting circuit 82 receives the RF signal 61 via theantenna 80 and converts it into one or more supply voltages (Vs). Thesupply voltage(s) power the other components (e.g., 84, 86, 92 and 94)so that they perform their specific tasks. For instance, the receiver 92is operable to convert an inbound message received from the sensingcomputing device into a baseband signal that it provides to theprocessing module 84. The processing module 84 processes the basebandsignal and, when appropriate, generates a response that is subsequentlytransmitted via the antenna 80 by the transmitter 94. For example, theinbound message instructs the wireless sensor to provide a respond witha pressure measurement and the stored ID of the item.

To obtain a measurement of a condition of the item, the sensing circuit58 senses the item. For instance, the sensing circuit 58 is producing achange to one or more of capacitance, inductance, resistance, resonantfrequency, and antenna loading of the wireless sensor as an indicationof the condition of the item. For example, when the sensing element 58is sensing for moisture, as the presence of moisture increases, theimpedance of the sensing element will decrease affecting one or more ofthe capacitance, inductance, resistance, and antenna loading of thewireless sensor. As another example, when the sensing element 58 issensing for gases, its resistance changes in the presence of gases suchas CO, CO₂, NO_(x), H₂S, O₂, and Cb. As a further example, when thesensing element is sensing for proximity, movement, or pressure, thesensing element experiences inductive changes created by eddy currentson nearby metal surfaces.

The changing electrical characteristics of the sensing circuit 58 causesa change in an RF characteristic of the RF front end 75, which includesthe antenna 80, the tuning circuit 90, and the sensing circuit 58. Notethat an RF characteristic includes an impedance (e.g., an inputimpedance) at a frequency (e.g., carrier frequency of the RF signal), aresonant frequency (e.g., of the turning circuit and/or antenna), aquality factor (e.g., of the antenna), and/or a gain. As a specificexample, the resonant frequency has changed from a desired resonantfrequency (e.g., matching the carrier frequency of the RF signal) asresult of the sensed condition.

The processing module 84 detects, via the detection circuit 35, avariance of the one or more RF characteristics from a desired value(e.g., the resonant frequency changes from a desired frequency thatcorresponds to the carrier frequency of the RF signal). When theprocessing module detects the variance, it adjusts the tuning circuit tosubstantially re-establish the desired value of the one or more RFcharacteristics. For example, the tuning circuit 90 includes an inductorand a capacitor, at least one of which is adjusted to change theresonant frequency back to the desired value.

The processing module 84 determines the amount of adjusting of thetuning circuit 90 and converts the amount of adjusting into a digitalvalue. The digital value is representative of the sensed condition ofthe item by the sensing circuit 58. For example, the digital valuerepresents a change in the condition with respect to a referencecondition (increasing temperature, increasing moisture level, etc.). Asanother example, the digital represents a measure of the condition(e.g., a temperature, a moisture level, a pressure level, etc.).

The processing module 84 generates a message regarding the adjusting ofthe tuning circuit (e.g., the message includes the digital value or anactual measurement if the processing module performs a digital value tomeasurement conversion function). The transmitter 94 transmits themessage to the sensing computing device 12 via the antenna 80 or anotherantenna (not shown).

Before the processing module 84 processes the sensed condition, it mayperform a power level adjustment. For example, the power detectioncircuit 86 detects a power level of the received RF signal. In oneembodiment, the processing module interprets the power level andcommunicates with the sensing computing device 12 to adjust the powerlevel of the RF signal to a desired level (e.g., optimal for accuracy indetecting the environmental condition). In another embodiment, theprocessing module includes the received power level data with thedigital it sends to the sensing computing device 12 so that thecomputing device 12 can factor the power level into the determination ofthe extent of the condition.

The processing module 84 may be further operable to perform acalibration function when the condition in which the sensor is known(e.g., in a room at a certain altitude, in a calibration chamber havinga set pressure, at a known temperature, etc.). For example, theprocessing module 84 receives a calibration request from a sensingcomputing device. In response, the processing module adjusts the tuningcircuit to establish the desired value of the RF characteristic(s)(e.g., resonant frequency, input impedance, quality factor, gain, etc.).The processing module then records a level of the adjusting of thetuning circuit to represent a calibration digital value of the wirelesssensor (e.g., records a digital value). The processing module maycommunicate the calibration value to the sensing computing device 12 aspart of the calibration process or send it along with the digital valueof a condition measurement.

FIG. 5 is a logic diagram of an example of determining a digital valueby a wireless sensor that begins at step 110 where the sensor IC of thewireless sensor receives a sensed condition of the item from the sensingelement (e.g., a change in an RF characteristic of the RF front end).The method continues at step 112 where the sensor IC determines an inputimpedance of the wireless sensor based on the sensed condition. Forexample, the sensor IC determines a change in the resonant frequency ofthe RF front end, which corresponds to a change in the input impedanceof the RF front end of the wireless sensor.

The method continues at step 114 where the sensor IC converts the inputimpedance into a digital value that is representative of the conditionof the item. For example, the sensor IC adjusts the tuning circuit suchthat the resonant frequency of the RF front end substantially matchesthe frequency of the received RF signal. The adjustment amount of thetuning circuit is determined and converted into the digital value. Themethod continues at step 116 where the sensor IC outputs, via theantenna, the digital value or a representation of the condition of theitem (e.g., the sensor IC interprets the digital value to determine ameasure of the condition of the item).

FIG. 6 is a schematic block diagram of an embodiment of an antenna 80and tuning circuit 90 of a wireless sensor 16. The tuning circuitincludes an inductor and a variable capacitor (e.g., a varactor, aswitchable capacitor bank, etc.). The capacitor is adjusted to retunethe RF front end's resonant frequency to substantially match the carrierfrequency of the received RF signal as the sensing element changes an RFcharacteristic of the RF front end due to condition changes of the item(e.g., temperature; moisture; pressure; concentration level of the item;and presence or absence detection of the item).

FIG. 7 is a schematic block diagram of another embodiment of a wirelesssensor 16 that includes the antenna 80, the transmission line 102, afirst tuning inductor 103, the sensor IC 17, a second tuning inductor105, and the sensing element 58. The tuning inductors 103 and 105 form atransformer that assistance in impedance matching of the sensor IC 17and the transmission line 102. As is shown, the antenna 80 is distallylocated from the sensing element 58 and the sensor IC 17.

FIG. 8 is a schematic block diagram of another embodiment of a wirelesssensor 16 that includes the substrate 100, the antenna 80, thetransmission line 102, a first tuning inductor 103, the sensor IC 17, asecond tuning inductor 105, and the sensing element 58. In thisembodiment, the sensing element 58 includes two parallel metallic traces(e.g., any conductive metal or electrically conductive material) thatform a capacitor. Each of the metallic traces of the sensing element hasa length and thickness and are separated by a spacing. The transmissionline 102 includes metallic traces that also have a length, a thicknessand are separated by a spacing. Variations in the length, thickness,and/or spacing of the metallic traces of the sensing element and/or ofthe transmission line 102 effect impedances of the wireless sensor.

The antenna 80 is shown as a dipole antenna with a ½ wavelength length,where each antenna leg as a ¼ wavelength length. In an embodiment, thelength of the transmission line is equal to or greater than ¼ wavelengthlength such that the antenna 80 is far enough removed from the sensingelement to minimize the RF communication adverse effects of the itembeing sensed. Note that the antenna 80 may be rotated 90 degrees fromthe orientation shown in the figure. Further note that the transmissionline 102 may have a different shape than a straight line. Still furthernote that the antenna impedance at RF and the impedance of thetransmission line are substantially equal and may be 77 Ohms.

In an embodiment, the antenna is disposed on single-layer PCB (e.g.,substrate 100) with dimensions of 360.84 mm×146.92 mm. The boardmaterial is a 5 mil Kapton (in other embodiments, any materialapproximating PET in terms of dielectric constant would be suitable).The copper (Cu) weight is 0.5 oz with a gold flash finish, with a whitesilkscreen and no coverlay/soldermask. In another embodiment that issuitable for volume manufacturing, the construction would be 9 μmaluminum on 50 μm PET with or without a thin (=12 μm) PET cover layer.

The inlay construction of the wireless sensor is 9 μm aluminum on 50 μmPET with a thin coverlay. The antenna requires 2 mm of spacer consistingof 2 layers of, for example, 3M VHB 5952. The spacer is backed by thinPET with metallization to form a consistent ground plane. Adhesive thenadheres the sensor IC to a metal surface. In some embodiments where theapplication of the sensor IC is expected to be onto inconsistentsurfaces in terms of planarity and surface treatment, including thickand rough non-metallic coatings [sound deadeners], the presence of thebackside plane integrated into the construction is critical.

The spacer may continue under the tail, but it is not required and thusenables flexibility and ease of installation. Since the slot line gap isonly 90 μm, the fields are tightly constrained and very tolerant ofinstallation variables. For example, the tail can be laid or tapeddirectly down to metal.

The transformer at the end of the tail cannot sit directly on metalbecause the presence of the metal detunes the transformer. A 2 mm spaceris placed between the transformer and a metal surface. A spacer is notrequired if the transformer is placed on any thick dielectric surface.In any configuration, dielectric materials can be placed directly on topof the transformer.

It is noted that terminologies as may be used herein such as bit stream,stream, signal sequence, etc. (or their equivalents) have been usedinterchangeably to describe digital information whose contentcorresponds to any of a number of desired types (e.g., data, video,speech, audio, etc. any of which may generally be referred to as‘data’).

As may be used herein, the terms “substantially” and “approximately”provides an industry-accepted tolerance for its corresponding termand/or relativity between items. Such an industry-accepted toleranceranges from less than one percent to fifty percent and corresponds to,but is not limited to, component values, integrated circuit processvariations, temperature variations, rise and fall times, and/or thermalnoise. Such relativity between items ranges from a difference of a fewpercent to magnitude differences. As may also be used herein, theterm(s) “configured to”, “operably coupled to”, “coupled to”, and/or“coupling” includes direct coupling between items and/or indirectcoupling between items via an intervening item (e.g., an item includes,but is not limited to, a component, an element, a circuit, and/or amodule) where, for an example of indirect coupling, the intervening itemdoes not modify the information of a signal but may adjust its currentlevel, voltage level, and/or power level. As may further be used herein,inferred coupling (i.e., where one element is coupled to another elementby inference) includes direct and indirect coupling between two items inthe same manner as “coupled to”. As may even further be used herein, theterm “configured to”, “operable to”, “coupled to”, or “operably coupledto” indicates that an item includes one or more of power connections,input(s), output(s), etc., to perform, when activated, one or more itscorresponding functions and may further include inferred coupling to oneor more other items. As may still further be used herein, the term“associated with”, includes direct and/or indirect coupling of separateitems and/or one item being embedded within another item.

As may be used herein, the term “compares favorably”, indicates that acomparison between two or more items, signals, etc., provides a desiredrelationship. For example, when the desired relationship is that signal1 has a greater magnitude than signal 2, a favorable comparison may beachieved when the magnitude of signal 1 is greater than that of signal 2or when the magnitude of signal 2 is less than that of signal 1. As maybe used herein, the term “compares unfavorably”, indicates that acomparison between two or more items, signals, etc., fails to providethe desired relationship.

As may also be used herein, the terms “processing module”, “processingcircuit”, “processor”, and/or “processing unit” may be a singleprocessing device or a plurality of processing devices. Such aprocessing device may be a microprocessor, micro-controller, digitalsignal processor, microcomputer, central processing unit, fieldprogrammable gate array, programmable logic device, state machine, logiccircuitry, analog circuitry, digital circuitry, and/or any device thatmanipulates signals (analog and/or digital) based on hard coding of thecircuitry and/or operational instructions. The processing module,module, processing circuit, and/or processing unit may be, or furtherinclude, memory and/or an integrated memory element, which may be asingle memory device, a plurality of memory devices, and/or embeddedcircuitry of another processing module, module, processing circuit,and/or processing unit. Such a memory device may be a read-only memory,random access memory, volatile memory, non-volatile memory, staticmemory, dynamic memory, flash memory, cache memory, and/or any devicethat stores digital information. Note that if the processing module,module, processing circuit, and/or processing unit includes more thanone processing device, the processing devices may be centrally located(e.g., directly coupled together via a wired and/or wireless busstructure) or may be distributedly located (e.g., cloud computing viaindirect coupling via a local area network and/or a wide area network).Further note that if the processing module, module, processing circuit,and/or processing unit implements one or more of its functions via astate machine, analog circuitry, digital circuitry, and/or logiccircuitry, the memory and/or memory element storing the correspondingoperational instructions may be embedded within, or external to, thecircuitry comprising the state machine, analog circuitry, digitalcircuitry, and/or logic circuitry. Still further note that, the memoryelement may store, and the processing module, module, processingcircuit, and/or processing unit executes, hard coded and/or operationalinstructions corresponding to at least some of the steps and/orfunctions illustrated in one or more of the Figures. Such a memorydevice or memory element can be included in an article of manufacture.

One or more embodiments have been described above with the aid of methodsteps illustrating the performance of specified functions andrelationships thereof. The boundaries and sequence of these functionalbuilding blocks and method steps have been arbitrarily defined hereinfor convenience of description. Alternate boundaries and sequences canbe defined so long as the specified functions and relationships areappropriately performed. Any such alternate boundaries or sequences arethus within the scope and spirit of the claims. Further, the boundariesof these functional building blocks have been arbitrarily defined forconvenience of description. Alternate boundaries could be defined aslong as the certain significant functions are appropriately performed.Similarly, flow diagram blocks may also have been arbitrarily definedherein to illustrate certain significant functionality.

To the extent used, the flow diagram block boundaries and sequence couldhave been defined otherwise and still perform the certain significantfunctionality. Such alternate definitions of both functional buildingblocks and flow diagram blocks and sequences are thus within the scopeand spirit of the claims. One of average skill in the art will alsorecognize that the functional building blocks, and other illustrativeblocks, modules and components herein, can be implemented as illustratedor by discrete components, application specific integrated circuits,processors executing appropriate software and the like or anycombination thereof.

In addition, a flow diagram may include a “start” and/or “continue”indication. The “start” and “continue” indications reflect that thesteps presented can optionally be incorporated in or otherwise used inconjunction with other routines. In this context, “start” indicates thebeginning of the first step presented and may be preceded by otheractivities not specifically shown. Further, the “continue” indicationreflects that the steps presented may be performed multiple times and/ormay be succeeded by other activities not specifically shown. Further,while a flow diagram indicates a particular ordering of steps, otherorderings are likewise possible provided that the principles ofcausality are maintained.

The one or more embodiments are used herein to illustrate one or moreaspects, one or more features, one or more concepts, and/or one or moreexamples. A physical embodiment of an apparatus, an article ofmanufacture, a machine, and/or of a process may include one or more ofthe aspects, features, concepts, examples, etc. described with referenceto one or more of the embodiments discussed herein. Further, from figureto figure, the embodiments may incorporate the same or similarly namedfunctions, steps, modules, etc. that may use the same or differentreference numbers and, as such, the functions, steps, modules, etc. maybe the same or similar functions, steps, modules, etc. or differentones.

While the transistors in the above described figure(s) is/are shown asfield effect transistors (FETs), as one of ordinary skill in the artwill appreciate, the transistors may be implemented using any type oftransistor structure including, but not limited to, bipolar, metal oxidesemiconductor field effect transistors (MOSFET), N-well transistors,P-well transistors, enhancement mode, depletion mode, and zero voltagethreshold (VT) transistors.

Unless specifically stated to the contra, signals to, from, and/orbetween elements in a figure of any of the figures presented herein maybe analog or digital, continuous time or discrete time, and single-endedor differential. For instance, if a signal path is shown as asingle-ended path, it also represents a differential signal path.Similarly, if a signal path is shown as a differential path, it alsorepresents a single-ended signal path. While one or more particulararchitectures are described herein, other architectures can likewise beimplemented that use one or more data buses not expressly shown, directconnectivity between elements, and/or indirect coupling between otherelements as recognized by one of average skill in the art.

The term “module” is used in the description of one or more of theembodiments. A module implements one or more functions via a device suchas a processor or other processing device or other hardware that mayinclude or operate in association with a memory that stores operationalinstructions. A module may operate independently and/or in conjunctionwith software and/or firmware. As also used herein, a module may containone or more sub-modules, each of which may be one or more modules.

While particular combinations of various functions and features of theone or more embodiments have been expressly described herein, othercombinations of these features and functions are likewise possible. Thepresent disclosure is not limited by the particular examples disclosedherein and expressly incorporates these other combinations.

What is claimed is:
 1. A method comprises: receiving, by a wirelesssensor, a request for sensed data from a sensing computing device,wherein the request is received via a radio frequency (RF) signal, andwherein the RF signal has a carrier frequency; sensing, by the wirelesssensor, an environmental condition of an item; determining, by thewireless sensor, an effect on an operational parameter of an RF frontend of the wireless sensor as a result of the sensing element sensingthe environmental condition and while receiving the RF signal;adjusting, by the wireless sensor, tuning of the RF front end tomitigate the effect on the operational parameter; equating, by thewireless sensor, an amount of adjusting of the tuning of the RF frontend to a coded digital value; and sending, by the wireless sensor, thecoded digital value to the sensing computing device via the RF signal.2. The method of claim 1, wherein the operational parameter comprisesone or more of: an input impedance; a quality factor; and a resonantfrequency.
 3. The method of claim 1, wherein the adjusting the tuning ofthe RF front end comprises one or more of: adjusting input impedance ofthe RF front end; adjusting quality factor of the RF front end; andadjusting resonant frequency of the RF front end.
 4. The method of claim1, wherein the sending the coded digital value comprises: backscatteringthe RF signal to include in the coded digital value.
 5. The method ofclaim 1 further comprises: the item having a property that interfereswith the RF signal or the item is in a container that has a propertythat interferes with the RF signal; receiving, by an antenna of the RFfront end, the RF signal with minimal interference from the propertythat interferes with the RF signal; and changing, by a sensing elementof the wireless sensor, the operational parameter of the RF front end asa result of sensing the item directly or via the container, whereinthere is physical separation between the antenna and the sensingelement.
 6. The method of claim 1, wherein the item comprises one of: abox, a personal item, a pet, an automobile component, an article ofmanufacture, an item in transit, a bodily fluid, a liquid, and gas. 7.The method of claim 1, wherein the environmental condition comprises oneof: moisture, temperature, pressure, humidity, altitude, sonic wave,human contact, surface conditions, tracking, and location.
 8. A wirelesssensor comprises: a radio frequency (RF) front end operable to: receivea request for sensed data from a sensing computing device, wherein therequest is received via a radio frequency (RF) signal, and wherein theRF signal has a carrier frequency; and send a coded digital value to thesensing computing device via the RF signal; a sensing element operableto sense an environmental condition of an item; and a processing moduleoperable to: determine an effect on an operational parameter of an RFfront end of the wireless sensor as a result of the sensing elementsensing the environmental condition and while receiving the RF signal;adjust tuning of the RF front end to mitigate the effect on theoperational parameter; and equate an amount of adjusting of the tuningof the RF front end to a coded digital value.
 9. The wireless sensor ofclaim 8, wherein the RF front end comprises: a receiver section; atransmitter section; an antenna operably coupled to the receiver sectionand the transmitter section, and a tuning circuit operably coupled tothe antenna, wherein the tuning circuit is adjusted to tune the RF frontend.
 10. wireless sensor of claim 8, wherein the operational parametercomprises one or more of: an input impedance; a quality factor; and aresonant frequency.
 11. wireless sensor of claim 8, wherein theprocessing module is further operable to adjust the tuning of the RFfront end by one or more of: adjusting input impedance of the RF frontend; adjusting quality factor of the RF front end; and adjustingresonant frequency of the RF front end.
 12. The wireless sensor of claim8, wherein the RF front end is further operable to send the codeddigital value by: backscattering the RF signal to include in the codeddigital value.
 13. The wireless sensor of claim 8 further comprises: theitem having a property that interferes with the RF signal or the item isin a container that has a property that interferes with the RF signal;receiving, by an antenna of the RF front end, the RF signal with minimalinterference from the property that interferes with the RF signal; andchanging, by the sensing element, the operational parameter of the RFfront end as a result of sensing the item directly or via the container,wherein there is physical separation between the antenna and the sensingelement.
 14. The wireless sensor of claim 8, wherein the item comprisesone of: a box, a personal item, a pet, an automobile component, anarticle of manufacture, an item in transit, a bodily fluid, a liquid,and gas.
 15. The wireless sensor of claim 8, wherein the environmentalcondition comprises one of: moisture, temperature, pressure, humidity,altitude, sonic wave, human contact, surface conditions, tracking, andlocation.